Surfer slang (although also extends to other boardsports, and surf sports) for a young surfer. Can also be used to refer to children in general, although usually they have some association with surfing/etc.

Although usually there is no ill-meaning behind the term, it is often used to poke fun at younger surfers. It can sometimes be used as a derogatory term when younger surfers are annoying, bad or otherwise difficult.

A possible etymology for the word may be from the Portuguese term 'grumete', meaning the lowest ranking person on board a naval ship - this word would have been used widely in South Africa in the period when surfing was becoming popular.

There are a lot of grommets surfing at the point today, dropping on on everyone.